Vehicle suspension



May 13, '1952 A. s. KRO-rz 2,596,904

VEHICLE SUSPENSION Filed Aug. 25, 1948 `A 2 SHEETS-SHEET l @MMM May 13, 1952 A, KRO-rz 2,596,904

VEHICLE SUSPENSION Filed Aug. 25, 1948 2 SHEETS-SHEET 2 Patented May 13, 1952 VEHICLE SUSPENSION Alvin S. Krotz, Akron, Ohio, assig'nor to The B. F.

Goodrich Company, New York, N. Y.,

ration of New York a corpo- Applicationr August 25, 1948, Serial No. 45,991

Thisv inventionrelates to vehicle suspensions and especially kto suspensions for vehicles which carry loads having a wide range of weights. 'I'he invention is also especially usefulin vehicles having small clearances between the frame and axle.

Objects Of the invention are to provide an improved vehicle suspension, to provide avariable spring rate suspension for cushioning'vehicles carrying large and small loads, to Vprovide for resiliently limiting the deflection of the wheels, to provide desirable automatic steering movement of the Wheels during deflections thereof as'when a vehicle rounds a curve, to provide for a desirablereaction of the vehicle to braking forces, to provide for obtaining different spring characteristicslwith small adjustments of the suspension system Without necessitating replacement of the springs, to provide simplicity of construction andto provide for convenience and economy of manufacture and installation. n

These and other objects will be apparent from the following description, reference being had to the drawings in which: Y, f f

Fig. v1 is a plan view of'a vehicle suspension constructed in accordance with vand embodying the invention. l

Fig. 2 'is a section taken'along'line 2-2` of Figl., .a a..

Fig." 3 is a section y y Fig-.4 is a view like Fig. 2 but showing a modifcation of the invention. 'y

Referring tothe drawings, an lembodiment of the invention which may be used on a heavy duty vehicle such asa bus is shown. The invention is especially suitable for buses as it permits `a. large amount of unobstruc'tedn'oor space because the springs. are conveniently disposed alongside the axle.A and kalso because it Aprovides effective vcushioning of large loads aswell as small loads.l

'I heassembly shown in Fig. 1 has a wheelsupporting structure such as an axle housinglll which` connects dual Wheels' which lare mountedV on stub axles encased in the axle hou's.` ing.V The wheels I I, I I may be driven by two engines disposed forwardof the axle (to the right' inuFig.v1). vThe engines propel driveshafts |72, I2 which extendrearward -to universal joints |3,'|3 which. accommodatev deflection `and fthen' extend into the axlev housing l0. where'y they are geared to the stub axles for driving the wheels I I, I.

A supported structure or frame I4 of -the vehicle comprises a transverse memberIS, forward of the axle housing Il)y and a-.transverse member I6 to the'rear of the'axle housing which support takenv along line 3--3 of y s Claims. y(c1. 2er-.21)-

, 2 the body of the vehicle or maybe part of the body. A Apair of torsion spring assemblies Il, I1 is mounted on the forward transverse member |5 and another pair of torsion spring assemblies I8, I8 is mounted on the rear transverse member |6. Each of the spring assemblies I1, and I8, I8,v of eachpair are preferably disposed at each side of the vehicle opposite to the spring assemblies'of the other pair.

Each of the spring assemblies I7', I'l and I8, I8 has a spring as Vshown in Fig'. 3v which has an inner shaft |9`which may be'rotatably mounted on brackets 20, 2liv mounted on the transverse members'iI-iland I6. AA sleevev 2| which may be split is'disposed about each shaft I9 and an annular elastic body of rubber-like vmaterial 22 is interposed between the' sleeve and shaft. The body of rubber-like material 22 may be bonded by suitable means such as vulcanization to the shaft [Sand sleeve 2|. f

Thesleevesl I, 2| aire mounted xedly in shells 23, 23 which Vhave inwardly projecting edges 24, 24, bent into theV space between the split portions of, thek sleeves.. The forward spring assem- 25 blies k|'|, Il have outwardly extending arms 25, 25

mountedon the shells 23, 23 and the rearward springl assemblies I8, |8 have arms 26, 26 mounted onthe shells 23, 23 of the springs for turning the sleeves 2|, 21| relative to the inner shafts I9, I9.

The arms y2,6, 26 extend forward toward the axle housing ||I in a substantially horizontal position and; yhave bearings 21, 2`| at the forward end for receiving pins 28, 28. Lugs 29, 29 are mounted on the' axle housing IU and have bearings 36, 3) for receiving pins 3|; 3|. which may be'split forl clamping the pins 28, 28

and 3|, 3 Iconnect the arms 26, 26 and axle housing I6. The pins 28,- 28 and 3|, 3| are clampedl between the splitportions of the link members 32, 32 at the end portions and are held in clamping vengagement by bolts and nuts 33 and 3II.k

The link members 32, 32 preferably'extend forward and upward from the arms 26, 26 to the lugs 29, 29 withjan oblique angle between the arms and link members under Vnormal load.

The arms 25,125 ofthe forward spring assemblies I extend Vrearwardly toward andare pivotally connected to the axle housing Ill. V It is'de-v sirable that the arms v25, 25 have anupward inclinationy from' the spring toward the axle housing; lowhenthe vehicle is carrying a normalk load. The arms' 25, 25 may be forked at the axlefhousing I0 as shown in Fig:l 1 andi may by serrations disposed in apertures of the arms which fit around and intermesh with the shafts or by other suitable fasteners. The rods 4I, 4I may be threaded and incorporateturnbuckles 42, 42 for adjusting the position ofthe inner shaft I9 to regulate the windup of the spring. As shown in the drawings the rods 4I, 4I for the arms 49, 40 on the shafts I9, I9'fortherear springs may extend upward and the arms 4I),r 48 on the shafts I9, I9 for the forward springs may extend downward with the rods 4I, 4I extending forward from the arms'to` a suitable portion ofY the frame (not shown).

Aradius rod 43 is disposed forward of theaxle housing` I at or about the axis of the vehicle. The radius rodv 43p is pivotally mounted atthe forward 'end on the forward transverse member.

Ijof the frame whilev the other end is pivotally mounted on an arm 44extendingdownwardly sition of the wheels (designated AC in Fig. 2) is much smaller than the effective moment arm AB for the normally loaded position of the wheels II, II and the resistance of the spring to turning is greater because of the increased increments of rotation of the arms 26, 26, all of which provides a greater stiffness of springing than is providedf at the normally :loaded condition of the vehicle.

The wheel assembly shown is positioned on the vehicle aft of the front wheels and the arrangement asv shown is conducive to easy steering of the vehicle because as the vehicle is turned into ai curve the wheels tend to turn into the curve fromthe axle housingI. The connection at the rear end of the radius rod 43 Acornprisesa bushingr, 45 of resilient rubber or other rubberflike materialin-an aperture in the rod. A pin 4B'isv mounted on the radius rod 43 and isA disposed for rotation in the bushing 45 `which accommodatesV lateral tilting Aof the axle housing IIJ relative ,to4

theframe I4., When the wheels II, II onone side of the ,vehicle are deflected a greateramount than the wheels on the other side,the axle housing I0 tends to tilt laterally and the VVresilient materalof ,the bushing is distorted permitting freedoin otmovement 4of the V,axle housing withoutv twisting of the radius rod 43.

In` operation, the vehicle is cushioned during deectionfthel wheels II, II by twisting ofthe annulaitbodies `22, 22 of resilient rubber-likematerial..in torsionalshear. Asthe wheelsII, II are-deectedand rise relative to -theframe l4'the axle housing II) 4moves ina path determined by thearms 25, 25 .of the forward spring assemblies I1, I1 andbythe radius'- rod 43. II,II frise in equal increments relative to the As the wheelsk frame I4. the anglebetween the .rearward arms 26,- rZIan'd link members 32, 32 changes and the arms are turnedthrough consecutively4 greater incrementsof rotation increasing the amount `of windupin the springs which results in an increase `in the stiffness; of the springing. In; ad:- dition-- the change inthe angle between the arms 26, 26, and vlink membersl 32,? 32 changes the length, of 'theY effective moment. `arm.v of, the springs (designated AB in Fig.f.2.for anormally loaded condition of the vehicle). In the em.-

bodiment shown inthe. drawing theeifective moment arm decreases and the resistance toY upwardmovement of the wheels. II, II increases las the A wheels riseV relative tothe frame.;.l4.. The combination of vthese reactions tdupward movement of theV wheels II, II- provides .a lvariable rate suspension with theY springing resistance stiffeningas the wheels, approach the bump position which occurs when-the link members 32, 32v and the ,arms 26, 26 approach alignment asshown in dot-dash lines invFig.-2. The effective moment arml for the heavily loaded or 4bump po-l -also.l` Thismcvement will be apparent from ob- 25, 25 -of the forward springfassembliesv I1, I1 asl shown-in FigvZ.v As'the vehicle rises relative to the v'wheels II, Il-theforward arms 25,25 swing the vwheels rearward.

The-combinationof these movements causesvrthe wheelsII, II to steer into a curve because as the vehicleturns 4the centrifugal force tends to tilt the vehicle -away fromithe axis about whichthevehicle turns. The resultant downward movement `ofV the frame relative to the outerwheels I I, I I lcauses them to move forward and tbe resultant upward-movement of the framel relative Vto the Yinner -wheels causes them to'move rearwardl andthe twoV movements turnthe axle housing I0 into thecurve. Theconnection of the radius rodV 43 to the axle housing I!!V accommodates'turning of the axle housing asfthe yieldable bushing^45 of resilientlrubber-likejmaterial provides flexibility Ipermitting tilting move-A ment,M of the connection.

The forward-arms 25, 25 are inclined yforward and ydownward while the radius rod v43 is 4inclined'forward and upward in aV converging relationship with the forward arms. Upon upward movement of the axle housing lII) v'relative to the frame I4 the axle housing tilts in a clockwise di-` rection as shown in Fig. 2 and the drive shafts I2, I2 aretilted downward which :reduces the deflection which thel universal joints I3, I3'must accommodate. c

A modification is shownY in Fig. 4 inl which armsj41,41':are mountedon theshafts I9, I9'of theA springs and extend upward from the shafts. The arms,41',. 41 are connected by a rod 48 Vwhich extends through an eyeV vof an' eye bracketv 49' The' mountedv on the frame I4 "of the vehicle. rod 48;', V48 isthreaded atthe eyebracket 49fjand is adjustably secured Vvto the eye bracket'by nuts 50,'50threaded on.a rod at opposite sides ofthe eyek bracket.V The arms, 41,I 41also maybe ad.-

justablysecured to the vrods 48,48 by nuts.5l,` 5|r threaded gonA therods. The arms 41, 41`have aperturesat the end portionsA through which' the rodsj 48,48i extend and vthe rodsihave `threaded portions adjacentV the apertures on. which 'the nutsi 5I1`;. 5l` may ,be threaded` for` adjustably clamping the arms on the rod.V f

In operationthe tendency for onejofthe arms, 41,141toturn is counteracted bythe ,other arm andthe eye bracket49 Von the frame I 4" 'orfbody of the vehi'cle"is-not subjected tothe fullmagni-J 5, tude of the forces.Y `For example, if the wheels Il rise relative to the frame lll'the resilient bodies'22, 22-ofrubber-like material of the springs tendv to move the shafts 19,--I9 in a direction whichwill move Vthe arms 41, 41 in opposite direc- Variations.,mayV be made without :departing from theinvention-as it is ing claims.

I claim: v k1. A vehicle suspension comprising a supported dened by the vfollow-y structure, a wheel-carrying structure extendingy transversely of said vehiclefa pairof' torsionY springs disposed at 'spaced-apart positions along4 said wheelecarrying structure, said Vsprings having armspivotally connecting said structures for cushioning 'relative' movementthereof, a second paireof torsion springsV disposed at positions opposing thev positions of springs of said rst pair of torsion springs, each of the springs of said secondpair being mounted on one structure and connected tothe other structure by linkages for transmitting relative movement of said structures of said spring, each of'sai'd linkages'com'- f prising an arm mounted on one of the'springsof said second pair and a link pivotally connected to said arm and tothe other structure, and a rod member pivotally connected to said supported structure and to said wheel-carrying structure at a position between said spaced-apartpositions and spaced vertically from the arm connections for limiting the fore and aft movement of said wheel-carrying structure relative to said supported structure and for turning said Wheelcarryingstructure about the pivotal connection of said armsto'said wheel-carrying structure to augment-the variation in the relative angular positions-ofl each said link relative to the'connecting arm in response to relativermovement lof said structures. v i n 2.1A ycushioning suspension Ycomprising Vsupported and supporting structures, an arm connectingsaid structures and pivoted on one of said structures for constraining relative motion -o-f saidy structures in predetermined paths-ai link having a'pivotal connectioniwith one ofjsaid structures and another link pivotally connected to said link and to the other of said structures, at least one of the pivotal connections of the links comprising a torsion spring, said torsion spring comprising inner and outer members mounted for relative rotative movement upon relative deiiection of said structures, and a body of resilient rubber material disposed between and mounted on said inner and outer members for resisting relative deection of said structures in torsional shear, the pivotal connections of said links with said structures being at points which have a different spacing at different load conditions, and said links being of such lengths that at a normal load they make an angle with one another approaching a right angle and at an extreme load they approach aligned positions whereby the effective moment arm of said torsion spring is greatly decreased and its effective spring rate to resist further relative motion of said structures is greatly increased under said extreme load.

3. A cushioning suspension comprising suppo-rted and supporting structures, an arm connecting said structures and pivoted on one of said structures for constraining relative motion of said structures in predetermined paths, a link having a pivotal connection with one of said structures and another link pivotally connected to said link and to the other of said structures, atleast one of the pivotal connections of the links comprising a torsion spring for resisting relative deflection of said structures by rotative 1 stress on said torsion spring, the pivotal connections ofsaid links with said structures being at points which have a different spacing at diierent load conditions, and said links being of such lengths that at a normal load theyAmake an angle with one another approaching a right angle and at an extreme load they approachy aligned positions whereby the effective momentarm vof said torsion spring'is greatlydecreased and itsl effective spring rate to resist Yfurther relative motion of said structures is greatly increased under` said extremeload.V i c c y 4. A cushioning suspension comprising supported ,and supporting structures, a Itorsion spring mounted on one of saidfstructures an arm mounted on said torsion spring and con-g;`

nected to the other of said structuresA forresisting relative motion of said structures by rota,-

tive stress on said spring and for constraining` the relative motion of said structures to predeter7 mined paths, a link having a pivotal connection with one of said structures and another link pivotally connected to said link and to the other of said structures, at least oneooi` the pivotal con.- nections of the links comprising a secondtorsion spring resisting relative deflection of said struc-4 tures by rotative stressr on said second torsion spring, the pivotal connections of said links with the said structures being at points which vhave a diierent spacing at different load conditions,and said links being of such lengths that at a normal load they make an angle with one another ap; proaching a right angle and at an extremeload they approach aligned positions whereby the effective moment arm of the said second .torsion spring is greatly decreased and its effective springV rate tor resist further relative motion of said structures is greatly increased under. said extremev load. v

5.V A cushioning suspension comprising supported and supporting structures, apair of. arms, each of said arms having one end pivotally connectedA to one of said structures and the other,

end pivotally connected to the other o f said structures for constraining relative motion of said structures in predetermined paths, said arms being in converging relationship and the pivotal connections of said arms to said structures having different axes individual to each arm'about which said arms may swing to provide relative turning movement of said structures, a link having a pivotal connection with one of said struc-i such-.lengths that Vat. a normal loadthey make anzangle. with one` another Vapproaching a right and itsv effective spring rate toreset further rela- Y tive motion of said. structureis .greatly increased under said extremeload.

6; A. cushioning suspension comprising supportedand supporting structures, a pair of arms,.r

eachof .said armshaving one end. pivotally. connectedto one lof said structures and.: the other. endpivotally connected to the other of said structures for constraining relative motion of saidv structures in predetermined.v paths, one of said arms being longer than the other of said armsito provide relative turning movement of said struc?. tures, a linky having a` pivotal connection with.

one of said structures and another link pivotally connected to saidlink and `to the other of said structures, at least one of the pivotal connections of -thelinks comprisingra torsion spring resisting relative deflection of said structures by rotative stress on said torsion spring, the pivotal connections of said links with said structures being at points which have avdifferent spacing at different load conditions, and said links being of such lengths that at a normal load they make an angle with one another approaching a right angle and at an extreme load they approach aligned*V positions whereby the eiective` moment arm the said torsion spring is greatly decreased and its effective spring rate to resist further relative motion of said structures is greatly increased under said extreme load.

7. A-vehicle suspension comprising a supported structure, a wheel-carrying structure', torsion springs disposed forward and ait of said wheelcarrying structure,` each of said torsion springs comprisingan inner and an outer member, a body of resilient rubber-like material disposed between and mounted on the said inner and outer members for resisting relative rotative movement of said members in torsional shear, one of'said members being mounted on said supported structure, each ofA said torsion springs having an arm mounted on the other I" said members and extending toward said wheel-carrying structure, one of the arms being connected to said wheel-carrying structure, for constrainingrelative movement of the structures in' predetermined paths, a link pivotally connected to the other of said arms and to said Wheel-carryingY structure, the ypivotal connection of said link with said wheelfcarryingistructure and the torsionspring i whichhas the armrconnected to said link having va'diierent spacinggat different loads', and the pivotally connected arm and linkY being vofV such'--le1flg-thsY that' ata normal load theyvmake an angle with one'anotherV approaching-anght angle and .at an .extreme load .they .approach aligned positions f whereby the effective moment arm of' the last-.mentioned torsion spring-isz greatly decreased and its effectivespring rate'.- to` resist further relative motion .of-said struc-i.- tures is greatlyA increased under said-extremev load.

8..- A vehicle suspension comprisingay supported. structure vandsa wheel-carrying structure; apair.i ofcarms disposed one above the other, each vof: saidxarmshaving one end pivotally connectedtoV said'supported structure and the otherendpivotV allyY connected to" said Wheel-carrying structurey for constraining movement of said.vvheel-carry-.- ing structure Vrelative yto said .supported struc-- ture in a predetermined up and down path`,`p a:

link having a pivotal connection `with said'wheelcarrying structure and' another ylinkzpivotally,

connected to said link and to said supported. structure, at least one of the pivotal connections of the links comprising a:torsion spring resisting deflection of said wheel-carrying structure: relative to said supported structure by rotative-f stress on said'torsionspring, the pivotal con-- nections of said links with the structuresibeing-f` at points which havea different spacing at diff ferent load conditions, and said links beingofV such lengths that at a normal load theymakean angle with' one another approaching'a right.

angle and at an extreme load they approach` aligned positions whereby the eiective moment arm of said torsion spring is greatly decreased.

and its eiective spring rate to resist further. relative movement of said structures is greatly increased under said extreme load,

ALVIN S. KROTZL REFERENCES CITED The following references are of record .in the.

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